1. Field of the Invention
The present invention relates to subsea connectors and devices for insulating the subsea connectors. More particularly, the invention relates subsea connector insulation devices that are installable using remotely operated vehicles (ROVs).
2. Description of Related Art
Subsea oil and gas field developments typically include one or more subsea wells and/or subsea components located at large depths and distances from a gathering platform (e.g., an oil gathering rig). The gathering platform may be a fixed or a floating platform. Production from the subsea wells is routed to the gathering platform through flowlines and/or subsea manifolds.
A field development may be a multi-well subsea development. The multi-well subsea development may include subsea structures such as subsea trees, manifolds, and/or pipeline end manifolds. These subsea structures may be interconnected by pipe jumpers (e.g., rigid pipe jumpers). The jumpers may mate up with the subsea structures using subsea connectors that mate with hubs on the subsea structures. In certain developments, production is routed from the trees into gathering manifolds, and from the gathering manifolds to pipeline end manifolds (PLEMs) and pipelines to the gathering platform.
As fluids flow from the subsea development to the gathering platform, the temperature of the fluids decreases, sometimes significantly, as heat is lost to the surrounding seawater. Measures may be taken to minimize heat lost to the sea water and keep fluid temperatures as high as possible to maintain low viscosity and good flow of fluids within the pipelines. Maintaining flow temperatures for the fluids is especially important when production of the fluids is shut down for any reason (e.g., when pumping of fluids in the pipeline is stopped for maintenance). Without insulation during shutdown, oil may slowly deposit wax or other solids on the interior walls of the subsea components.
Typically, the pipeline itself and piping in the PLEMs, manifolds, trees, and jumpers are insulated to inhibit heat loss to the surrounding seawater. The insulation may be pre-installed on the piping in a manufacturing stage before the structures are installed subsea.
The connectors on the ends of the jumpers, however, cannot be insulated prior to subsea installation. The connectors have moving parts and mating surfaces that have to interface with external tools during the installation process. These features inhibit placing insulation on the connectors prior to installation. Thus, insulation is placed on the connectors “in place” (e.g., after the jumpers are installed). Without insulation, significant heat losses would take place from the connectors.
Remotely operated vehicles (ROVs) are used in many subsea operations to perform work that has been traditionally performed by divers. ROVs may be used to install and/or work on many subsea structures, components, and/or connectors. ROVs may provide for safer and/or more efficient operation than using divers in certain subsea environments (e.g., deep subsea environments).
Current connector insulation systems in the subsea industry typically use insulation that has been molded into a shape that conforms to the outer contours of a connector. The molded insulation may be made as, or split into, parts so that the insulation can be put together during installation. The molded insulation may be in the form of pre-molded and/or rigid blocks (e.g., syntactic foam blocks, or syntactic foam blocks with glass spheres). In certain instances, an ROV is used to install the molded insulation on the connector after the jumper is installed. A can or housing may be placed around the molded insulation to hold the insulation in place. This configuration is generally referred to as a “dog house” type insulation.
The “dog house” configuration is inefficient in providing insulation against heat loss to seawater. The molded insulation in the “dog house” configuration typically does not achieve proper (e.g., positive) contact between the insulation and the surface of the connector. The improper contact does not provide a complete seal between the insulation and the surface of the connector. Thus, heat loss due to convection of seawater between the insulation and the surface of the connector may be significant.
In addition, an ROV may have difficulty installing a “dog house” configuration because, for example, the operator of ROV may not be familiar with or trained to install the insulation. “Dog house” configurations may also be expensive to manufacture (e.g., the molded insulation may have a cost on the order of the cost of the jumper).
Thus, there is a need for insulation systems and/or devices for subsea components (e.g., connectors for subsea jumpers) that are easy to install and provide an efficient insulation barrier between the component and the surrounding seawater. Such systems and/or devices may provide a substantial seal against a surface of the subsea component that inhibits fluid from flowing or circulating between the insulating device and the subsea component.